Table 1.

Indications for Blood Transfusions

When rapid correction of anemia is required to stabilize the patient’s condition (e.g., acute hemorrhage, unstable coronary artery disease)Red cell transfusion in patients with acute hemorrhage is indicated when there is: (1) rapid acute hemorrhage without immediate control; (2) estimated blood loss of >30%–40% (1500–2000 ml) with symptoms of severe blood loss; and (3) estimated blood loss <25%–30% with no evidence of uncontrolled hemorrhage if there are recurrent signs of hypovolemia despite colloid/crystalloid resuscitation. In patients with certain comorbid factors, transfusions may be necessary with less blood loss (69).
Studies evaluating the importance of anemia and the role of transfusion in the setting of an acute coronary syndrome (i.e., unstable angina, myocardial infarction) have reached differing conclusions.
The American College of Cardiology/American Heart Association and American College of Chest Physicians guidelines did not make any recommendations concerning the potential benefit or risk of blood transfusion in the setting of an acute coronary syndrome (70,71).
Although anemia occurs frequently in patients with heart failure, limited data are available on treatment of anemia in this population.
Correction of anemia has not been established as a routine treatment in heart failure, as noted in the 2005 American College of Cardiology/American Heart Association guidelines, the 2006 Heart Failure Society of America guidelines, and the 2008 European Society of Cardiology guidelines (7274).
General indications for red cell transfusion may be applied to patients with acute coronary syndrome and/or heart failure; however, careful attention to volume status is indicated when there is coexistent renal impairment.
When rapid preoperative hemoglobin correction is requiredCriteria have been proposed for the administration of perioperative transfusions, as follows (69):
 Red cell transfusions are generally not recommended when hemoglobin level is ≥10 g/dl in otherwise healthy person.
 Red cell transfusions should be given when hemoglobin level is <7 g/dl.
 When hemoglobin level is <7 g/dl and the patient is otherwise stable, 2 units of packed red cells should be transfused, following which the patient's clinical status and circulating hemoglobin should be reassessed.
 High-risk patients (those age >65 years or those with cardiovascular or respiratory disease) may tolerate anemia poorly and may be transfused when hemoglobin level is <8 g/dl.
 For hemoglobin level 7–10 g/dl, the correct strategy is unclear.
When symptoms and signs related to anemia are present in patients in whom ESA therapy is ineffective (e.g., those with bone marrow failure, hemoglobinopathies, ESA resistance)Patients with chronic anemia (e.g., those with bone marrow failure syndromes or hemoglobinopathies) may be dependent on red cell replacement over a period of months or years, which can lead to iron overload.
Approximately 200 mg of iron are delivered per unit of red cell; this iron is released when hemoglobin from the transfused red cell is recycled after red cell death.
Given the progressive loss of red cell viability that occurs during storage, the “freshest available” units should be selected to maximize post-transfusion survival
Hemosiderosis can produce organ damage when the total iron delivered approaches 15–20 g, the amount of iron present in 75–100 units of red cells, as occurs in conditions such as thalassemia or sickle cell disease.
The issue of red cell transfusion in patients with congenital or acquired hemolytic anemia is more complex.
When symptoms and signs related to anemia are present in patients in whom the risks of ESA therapy may outweigh the benefitsESAs should be used with great caution, if at all, in patients with CKD with active malignancy, a history of malignancy, or a history of stroke.
  • ESA, erythropoiesis-stimulating agent.